As do you, PBP. Iowa would have difficulty being independent while surrounded by an unfriendly neighbor, but California has the key ingredients for independence, even with an unfriendly neighbor.
Not really, they are super dependent on inter-continental sources for power, food, timber, etc. To import them from over-seas would further bankrupt an already failing economy.
You are also forgetting that the only reason they have more going out then coming in is taxes on extremely high income residents. If these residents agreed to succeed from the union they would have to agree to pay greatly increased state taxes for the state government to have a any real money coming into it. They would also have to realize they would then lose one of their major sources of income which is TV and films. Since they would not be exporting these products to the USA as easily profits would disappear.